UBC Theses and Dissertations
Biomechanical analysis of the dislocate Borchardt, Wallace James
The purpose of this study has been to make a biomechanical analysis of the dislocate as performed on the still rings. All testing was done in the gymnasium at the University of British Columbia with each of the five subjects taking three trials. Cable tension was monitored with strain gauges attached in series withthe ring cable. Each trial was filmed, and film and force records were synchronized with a flash gun which caused a timing mark to be placed on the chart recorder paper. When the subject felt he was ready the first of three trials was executed. There was a two minute rest between each trial to negate any effect of fatigue. After the completion of the third and final trial the subject was asked which trial he thought was the best of the three. The film record of the dislocate was later shown to a panel of experts who rated each dislocate. The rating by the panel of experts allowed each dislocate to be ranked in order of excellence. This rank order was the chosen criterion against which the biomechanical measurements were evaluated for the aim in coaching gymnastics is eventually to satisfy the subjective impression of the judges. The information recorded by the film was refined with the use of the Vanguard Motion Analyzer. Obtained were the following measures. a) position of the rings b) body position c) displacement of noted body landmarks The following conclusions were drawn from this study: 1. The patterns of force and body actions are similar for all subjects. Given these similarities it is difficult to identify measures which correlate highly with good performance. 2. The angular velocity of the movement of the legs at the second and third peaks of force is not well correlated with either experts' ranking (r = 0.18) or maximal force (r = 0.25). 3. The following are poor predictors of performance in the dislocate: a) Total range of angular displacement of the ring cable. b) Time (frames) between the second and third peaks of force. c) Angular displacement of the ring cable during the second and third peaks of force. d) Kipping angle. e) Amount of preparatory vertical drop of hips in the kipping phase. 4. Better performers are those who maximize the upward force during the kipping phase by accentuating the rise of the hips over that of the ankles. Consequently it is suggested that those teaching this activity concern themselves with methods of maximizing the upward thrust of the hips in the kipping phase. It is felt that this phase is the foundation block upon which the dislocate is built.
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